
FDII and Form 8993: How U.S. C Corporations Hit a 13.125% Effective Tax Rate on Foreign Sales
A working guide to the FDII (now FDDEI) deduction on Form 8993 — which U.S. C corporations qualify, how the Section 250 math drops the effective federal rate to 13.125% on foreign-derived income, the taxable income limitation, documentation the IRS expects, and how OBBBA simplifies the calculation starting in 2026 by removing the QBAI step and expense allocations.










